I have been working on a rpg style game for a couple of months now and am getting to
the point where I have my backbone ready. So now it is time to start developing
character, dialog, the terrain est. But alas I am not the most
creative person the world has ever known. So this is me asking, please help me
with some theme ideas that you guys would like to play. If you have bright idea
and I agree that it is a bright idea: I will give you beta access to the game
once it gets to that point.

So let me get this straight. You have built the technical game but don't have any idea or content for it?

What if I say I want the game to be set in space in zero gravity and I want turn-based combat with action points, insta-kill mechanics with no health points, no equipable or consumable items, 3 tiered gameplay (fps, group combat. space life sim/RTS troop management) You would say your engine can't do it and you would need to scrap/remake/make from scratch large parts of it. There's a reason you work on the idea first before building the game mechanics.

That being said I'm sure you'll have no difficulty in finding idea guys who think they have the best idea ever and can't do anything else but think of new features for you to implement that they think would be cool at first.

My point was how can you be making something like that when you don't know if the game will be Final Fantasy, Kingdom Hearts, Fallout or Pokemon? You are coming at this backwards.

By making certain choices in creating the "backbone" you have already in fact designed your gameplay to certain style. You have to state the outlines you have chosen in order to keep people's suggestions in line with what you already have.